Floor CPM

Floor CPM (floor cost per mille) is the minimum price per 1,000 impressions a publisher sets for their ad inventory. Any bid below the floor is rejected. Floor CPMs serve two functions: they prevent inventory from being sold at below-market rates, and they signal quality to advertisers — a newsletter with a $10 floor CPM signals that the publisher believes their audience is worth at least $10/thousand. In MailAdx's Publisher Portal, publishers can set global floor CPMs across all placements, per-placement floors, or per-advertiser-category floors. Floor CPM management is one of the most effective levers for increasing newsletter ad revenue — setting floors too low leaves money on the table; setting them too high reduces fill rate.